The ever-advancing field of medical science continuously seeks new and improved diagnostic tools.
In early years, the diagnostic tools were largely represented by outward physical manifestations, such as blood pressure, temperature, chills, and the like. These manifestations were conditions and parameters that could be simply observed or measured from outside the body.
In more recent times, certain tools, such as endoscopes, have been developed that allow penetration of certain body tracts and cavities in an attempted to gather additional diagnostic data. For example, it is common today to use an endoscope-like device for a colonoscopy or sigmoidoscopy, to visually inspect the lower gastrointestinal tract. Endoscopes are also used to inspect other mammalian cavities. For example, in veterinary science, endoscopes are commonly used to inspect nasal cavities of horses and other animals.
There are a number of tracts in a mammalian body. These include the gastrointestinal tract, which extends from mouth to anus, the reproductive tract, the auditory tract, and the respiratory tract.
Considering a mammalian gastrointestinal tract for the moment, there is a large amount of physiological data that is potentially available within such tract. This data could include sensed parameters, such as pH, pressure, temperature, transit time, the presence or absence of a disease marker, the presence or absence of some other diagnostic marker, the presence or absence of an antibody or antigen, subsurface imaging, conductance, or even an electrical signal. In addition, it may be desirable to topically apply medicaments to a particular situs within such a tract, or, alternatively, to take a fluid sample at a selected location within such tract.
To this end, various radio telemetry capsules have been developed. Basically, these are small pill-like devices that can be ingested or swallowed by a patient. The capsule may have a sensor to determine a physiological parameter of the gastrointestinal tract. Some devices contemplate that the parameter be sensed and transmitted by an RF signal to an extra-corporeal antenna or receiver. For example, U.S. Pat. No. 3,739,279 appears to disclose an oscillator circuit for such an ingestible capsule. This patent then discloses a type of Colpitts oscillator which may be used in association with a telemetry sensor for determining physiological information within the patient's body. This patent recites that earlier telemetry systems have been developed for transmitting information such as temperature, pressure, specific ion activity, pH, pK and the like via an ingestible radio capsule.
Others have attempted to develop ingestible capsules that can be used to transmit a video signal to a location outside the body. References teaching this concept are shown and described in U.S. Pat. No. 6,240,312, B12 and in an internet article “Capsule Endoscopy Gets Map, Compass”, http://www.gastroendonews.com/cgi-bin/wwread.pl?cat.=gastro&art=gen0802-01a.htm (Aug. 27, 2002). Still another reference is an article by Brad Lemly, “Ted Med”, Discover (April 2003) [at pp. 70 et seq.]. This article even has a photograph of an ingestible video capsule manufactured by Given Imaging.
Other references for measuring temperature are provided in U.S. Pat. Nos. 4,844,076 and 4,689,621.
Other references have been directed toward dispensation of medicaments at selected sites within the gastrointestinal tract. See, e.g. U.S. Pat. Nos. 4,425,117, and 6,245,057.
Still another report on such ingestible capsules, appears in Milner, “Advances In and Prospects for Bio-Telemetry”, symposium on Bio-Telemetry (Pretoria 1971).
Still another reference appears in an article by Alexandra Strikeman, “The Programmable Pill”, Technology Review (M.I.T. May 22, 2001) [also available at http://www.technologyreview.com/magazine/may01/strikeman.asp].
Therefore, it is clear that others have attempted to develop ingestible pills or capsules for sensing and determining various physiological parameters, and broadcasting them via an RF signal to an extra-corporeal receiver.
However, the values of such sensed parameters may not be sufficient in and of themselves. Indeed, it is also important to know the location of the pill at the time the physiological parameter is sensed. To this end, U.S. Pat. No. 5,279,607 discloses an ingestible telemetry capsule with a means to determine location of the capsule. The '607 patent also discloses the capsule as having a medicament dispensing function. Thus, according to this patent, a capsule may be ingested to map the gastrointestinal tract. Thereafter, another capsule, this one containing a medicament, may be ingested. This capsule may be caused to dispense its medicament at a desired location within the body.
U.S. Pat. No. 5,395,366, discloses a concept related to the '607 patent. However, according to this device, a fluid sample may be taken into a compartment in an ingestible capsule at a selected location within the body.
While these devices, taken individually and collectively, show the state of, and advances in, the art, it is believed that it is now possible to determine the current or real-time location of a capsule within a tract in a mammalian body. It is also believed that this improved location-sensing method, may be used together with corroborative data provided by the sensors themselves to verify the location within the body.